Parts of motorcars, such as doors, bonnets, etc., are made by press-molding a steel plate using a press mold. Since the press mold is expensive, for a mold for producing a small amount of the parts such as trials of these parts or parts for specific use, a zinc alloy mold is used. In the case of using the zinc alloy mold, the precision of almost the same as a design is obtained for small-sized parts but as a press mold for large-sized parts, there are problems that a casting strain is large and it is difficult to keep the precision.
As one of the solving means, a mold using a zinc alloy and a resin has been used. The mold using a zinc alloy and a resin is a mold prepared by making a base mold using a zinc alloy having a low melting point and capable of reusing by melting and forming a surface resin layer on the surface thereof by casting and since the base mold made of a zinc alloy can be reused, the cost for the press mold can be reduced as disclosed in JP-A-58-151925 (the term "JP-A" as used herein means an "unexamined published Japanese patent application").
Also, as the casting resin which is used for making the mold using a zinc alloy and a resin, an epoxy resin containing an iron powder has been generally used. However, a conventional mold using a zinc alloy and a resin has a disadvantage that the pressing number is restricted since if the pressing number for parts is increased, the surface of the resin is abraded and hence the casting resin which is used for making the mold using a zinc alloy and a resin has been desired to give a cured product excellent in abrasion resistance.